Nucleated hydrocarbons and method of synthesizing them



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NUCLEATED HYDROCARBONS ANDAMETHOD OF SYNTHESIZING THEM L H. JAMES 2,345,704

rneniedfApr. 4, i944 NUCLEATED HYDROCARBONS AND METHOD F SYNTHESIZING THEM Ioseph Hidy James, Pittsburgh, Pa., assignor to Clarence?. Byrnes, Pittsburgh, Pa., trustee I Application April 9, 1940, Serial No. 328,699

14 Claims. (Cl. 260-883.4)

My invention relates to an improved motor fuel of high octane rating, and to methods of synthesizing the same from mineral oil or frac-- tions thereof. It relates mainly to obtaining nucleated hydrocarbons of high octane rating by employing a partially oxidized product of hydrocarbons preferably obtained by my well known vapor phase partial oxidation process. By nuclear or nucleated I refer to hydrocarbons in which the molecular formation is more bunched, clotted, or nuclear, compared to the normal straight chain hydrocarbons or' which ordinary petroleum mainly consists. Examples of nucleari form are aromatics or ring-bodies, naphthenic hydrocarbons, and hydrocarbons of branched-chain structure. Aromatics are expensive to prepare; and the` main object of my invention is to obtain a motor fuel having high no knock properties by a simple and cheap process by whlchvbranch-chain molecules are obtained by alkylation of hydrocarbons; other nucleated forms are usually present as a result of the new process employed. The invention relates mainly to alkylating products obtained from partial oxidation of petro leum or its fractions by a gas containing free oxygen or by oxygen-yielding metallic oxides, and preferably where the partial oxidation product or a fraction thereof is cracked after partial oxidation, or is partially cracked during partial oxidation in the vapor phase. In my well known vapor phase process of partial oxidation, incidental cracking occurs, greater with a higher' temperature within the partial oxidation range, but I prefer to crack as an after step-either by ordinary thermal cracking with or without superatmospheric pressure or by catalytic cracking. However, cracking also may be carried oui' prior to the step of partial oxidation. Furthermore, where vapor phase oxidation is used, some unsaturated bodies are produced such as olefins, and these may be alkylated by addition of alkyl groups at the same time as the oxidation products which I have found ,peculiarly adapted therefore. Again polymerization of olens to form arbmatics and other nuclear bodies occurs in and as a result of cracking of my oxidation product, especially when performed in vapor phase, in the presence of a cracking catalyst, as I have found in several trials. The alkylation may be and preferably is carried out in vapor or gaseous or vapor-gaseous phase, though it may be done with the oxidized product in liquid phase. If a cracked oxidized or an oxidized and f cracked product is alkylated, the alkyl groups may be added to both the oxygen derivatives and the hydrocarbons having double bonds or unsaturates. Even where a special cracking step is carried out after oxidation, various oxidized bodies are still present as well as unsaturated hydrocarbons or olefines. The conditions of alkylation vary in dinerent cases as to thermal and pressure conditions. and as to the catalyst which is preferable for the particular case. The use of the preliminary partial oxidation step produces several mixtures amenable to alkylation. i,

As a catalyst I prefer, for alkylation purposes,

f a compound of aluminum, such as the acid silicate or I may use aluminum oxide. I may use silicates of the rare metals such as molybdenum, vanadium, tungsten, uranium. etc. Some of these may be prepared for example, by adding a soluble salt of the rare metal such as a chloride or sulfate therefor, such as various refractory materials, l

including clays, silicates, etc., or I may use rare metal compounds or complexes with each other. These catalysts also have the burn out adl vantage noted above.v

With any of the above `catalysts or catalytic mixtures, I may either use in series with, or in admixture with them, dehydrating agents (since the alkylation of most of the oxidized bodies really involves dehydration) such, as phosphoric anhydride, phosphorus pentoxlde, aluminum oxide, in fact, any compound that will remove water and in turn lose water at a suitable temperature, thus becoming regenerated.' I may also use these dehydrating catalysts, such as A1203, independently of the reforming silicate catalysts. The temperatures used in these reactions may vary, depending on the material being treated and the catalyst used, all the way from C. to 500 C. To illustrate the availability of gas mixtures formed in the original catalytic oxidation and in the cracking 'of the oxidized product; I here submit somef example analyses as follows; 1. Gas mixture recovered by the absorption from the exit stream during catalytic oxidation of a gas oil. Typical analyses-of the exit stream and oi the mixture obtained by absorption are given below:

Exit st Percent by volume Car diende is @les is@ een .s Carbon monomdar 3.3 @draden .3 Paramus es m; 14.@ Nitrogen ich@ Recovered' iro aicove exit by ahsoria= tion:

@ienne Ear- 'er hy volume 2am i252 2. Analysis oi gas formed dwing cracking oz? above oxidized ses oil at Zilli las. pressure and 496 C.: n

, Percent by I will now taire up speciio examples o mixtures to be nucleated or alirylated, these congtaining both the group oi omdised and cracked bodies (with or without unsaturatedsl on the one hand, and of saturated hydrocarbons on the other hand. First, the adding to a cracked and oxidized hydrocarbon of the 'non-aromatic type of any of the following:

(a) Since the pressure-thermal cracking oi the vapor phase catalytic oxidation product results in a liquid and a vapor-gaseous mixture.

`I may carry out the alkylation step (action ci certain catalysts to be described later) on this total mixture. In Figure 1 I show diagrammatically apparatus for performing this step, A representing a thermal cracking apparatus having burner 2, outlet 3 for combustion products, and cracking coil 4 with valved inlet 5 for feeding in the partly oxidized product. From the cracking coil 4, valved pipe 6 leads to a vertical tubular chamber ,'l containing alkylating catalyst in powered and lump form and having a surrounding jacket 8 containing a heat transfer medium.

From the bottom of allcvlating 'chamber 1, valved pipe 9 leads through condenser ill to receiver H forcondensate, the non-reacting gases passing ofi' through pipe l2.

(b) I may alkylate the liquid cracked catalytic oxidation product by means of natural Sas, or other aliphatic hydrocarbons,V preferably a' mixture which contains only the hydrocarbons which individually are gaseous at ordinary temperature and pressure. In Figure 2 showing one form of apparatus, a cracking apparatus is shown similar to that of Figure 1, designated by similar numerals with the letter a added. From apparatus A, pipeja leads to cooling condenser I6 and liquid receiver l1, having exit I8 to convey accesos the uncondensed vapor-gas mixture to storage, vaived' conduit it leads the liquid condensate to vaporizer-mixer Id'having valved inlet pipe GES for natural gas or other desirable gas.. From mixer Ml, pipe 5b leads to catalytic alkylation apparatus lo, du similar to that or Figure l; and sarly pipe @u leads therefrom through condenser itla to receiver tio having vapor gas outfl let pipe tra.

(ei'lihe foregoing cracked product may be allryiated by retaining the vapor-gaseous oongeners as noted, ned with natural gas. in this oase, as illustrated in Figure 3, l modify the apparatus shown in Figure 2 by leading the vapor-gas mixture through Vvalved pipe ith from the condenser receiver to the lower part oi the mixer Mib, the natural or other gas entering as before through valved pipe (15h. The mixture passes from the mixer Mb through pipe @h to niks/lation chamber lo surrounded 'by heat transier` medium jacket to. From the alkylation chamber, pipe Sib leads through condenser lh to receiver lib for condensed liquids, iZb being the exit pipe for non-condensed vapor-gas mixture. pipe iii oi Figure 2 as it contains only the vapors and gases from the condenser receiver.

(d) The vapor-gaseous mixture which forms during the original catalytic oxidation and which may be separated from the nitrogen and any useless substances by absorption in acetone, oxidined oil or other suitable solvent, may be used as an alkylating agent alone or admixed with anyl or all of the gaseous or vapor gaseous mixtures given in (a), (b) and (c). in this case, using, for example, apparatus similar to that of examples (c) (b) and (c): I may use for the alkyiation reaction the oxidized bodies and hydrocarbons separated from the original exit stream of vapor-gas formed during the vapor-phase catalytic partial oxidation step.

Again using the apparatus of Figure 2, i may convey this vapor-gas exit stream from the oxidining step into the vaporizer mixer it instead of natural gas and may there mix either the liquid products from the cracking of the liquid oxida- `tion product or the vapor gaseous products thereof or the total of such products (liquid and vapor gaseous).

(e) i may conduct the cracking of the oxidized oil in such a way as to produce essentially 'a vapor-gaseous mixture. This I may admix with any or all of the gaseous and vapor-gaseous mixtures and subject the whole to pressure temperature and catalytic conditions to bring about alkylation. In this case using the apparatus of l Figure 2 and violent or extreme cracking condisaturated hydrocarbons.

tions sufcient to produce approximately a vapor gaseous mixture, I may close the vapor gas outlet i8 and feed the vapor-gaseous mixture into the mixer I4; together with either vapor-gases absorbed from the product from the oxidizing step beyond the condenser therefor; or natural gas, or both.

(j) I may ofcourse admix any two of the above gaseous and vapor-gaseous mixtures and subject them to the appropriate catalytic and other conditions. For example, the "oxidation gases or vapor-gases have the olenes and oxidized bodies necessary for one part of our mixture, so that there is added any of the above gaseous or vapor-gaseous mixtures containing (a) AThe vapor-gaseous mixture resulting from the pressure thermal cracking o! the main oxida- In such case ith would be connected to y treated in the vapor phase by passing it overv an tion product contains both the above groups of reactants, and may itself be subjected to alkylating conditions as noted.

(h) As a further example of the various combinations of materials and steps possible, the following may be cited: A

I have found that there is a remarkable difference with reference to the degree of catalytic oxidation, between the hydrocarbons which are gaseous at ordinarytemperature and those of higher molecular weight, particularly those in kerosene and gas oil fractions. The upper limit of temperature which should be used in the vapor phase catalytic oxidation of kerosene or gas oil hydrocarbons is around 400 C.' At this temperature the hydrocarbons of natural gas, consisting principally of methane, ethane, propane, butane and pentane, are only slightly attacked, the attack here being on the higher molecular weight bodies. We may then mix with the heavier vapors of gas oil (or other cracking stock), the lower molecularl weight bodies of natural gas before carrying out the catalytic oxidation. The gas oil vapors will be attacked but the natural gas hydrocarbons only very slightly. The issuing mixture will contain olenes and oxidized bodies resulting from the oxidation attack and accompanying decomposition (where the temperature is 380 to 400 C.) and the very slightly attacked natural gas-hydrocarbons. This mixture is then preierab'ly subjected to pressure-thermal or to catalytic cracking, followed by the catalysts used for the alkylation as we have the two groups of compounds needed to synthesize nuclear hydrocarbons (oleiines and oxidized bodies on the one hand and saturated hydrocarbons on the other).

It is also evident that within my invention other mixtures for alkylation may be prepared, such as for example, that obtained by catalytic oxidation of natural gas raised to the temperature where the propane, butane, and pentane are attacked to form oxidized bodies and olefines, which react with the unchanged hydrocarbons when subjected to the alkylation catalysts.

In like manner the partially oxidized natural gas just cited, may be mixed with the gases from ordinary pressure-thermal or from catalytic cracking and subjected to the action of alkylation catalysts.

I may also subject ordinary cracking still gases to catalytic oxidation. This can be done with or without the admixture of natural gas, since here the temperature can be kept vwell below that `at which the heavier natural gas hydrocarbons are attacked, because we are attacking only the olenes in the cracking still gas. prepares the mixture of oxidation products and olenes on the one hand, and saturated hydrocarbons on the other, for alkylation.

I may carry out the vapor phase oxidation of a cracking stock, such as gas oil, under conditions suiliciently drastic (very high temperature and high air ratio) to yield a product (oxidized and cracked) which consists largely of gaseous or vapor-gaseous material. the removal of heavier products, may then be subjected to vapor phase catalytic alkylation, or it may be mixed with natural gas prior to alkylation. The oil may be cracked, if desired, before the step of partial oxidation. I will now give a specific` example of my alkylation process, as follows:

An oxidized mixture boiling within the ordi- -nary gasoline range (60 C. to 200 C.) was This material after alkylating catalyst in a 2 inch tube, 14 inches long. The tube was filled with the catalyst in the `shape of balls about grape size. 'nie fem of oxidized oil was at the rate of 100 c. c. per hour, and the temperatureof the catalyst chamber was 325 C. A condensing system was, provided. A recovery of 941% by volume was obtained and 94% of this distilled under.210 C. This product showed thefollowing analysis (percent by volume): oxidized bodies and oleiines, 32.2%; aromatic hydrocarbons, 24.8%; naphthenic hydrocarbons, 23.8%; and saturated aliphatic hydrocarbons, 19.2%. This analysis shows that from a mixture consisting essentially of.'

olenes and oxidized bodies, a marked increase was made in saturatedaliphatic hydrocarbons and in aromatic and naphthenic hydrocarbons, showing that forces were at work under catalytic action, causing polymerization and alkylation.

It is obvious also that I may mix natural gas with the vapors of the cracking stock before the This again drastic (extreme temperatures and high air ratios) oxidation, nally subjecting the vaporgaseus portion of the resulting oxidized and y ated ,and the best temperature for the catalysis of the alkylation. 'Where the mixture being treated is gaseous or vapor-gaseous, lower temperatures may be used to advantage since with certain catalysts the reaction takes place at a temperature as low as 7 C.

Referring again to the main cracked oxidation I mixture, with the proper catalysts further cracking takes place as well as alkylation. I'his is an advantage for since alkylation increases the molecularweights it is well to start with the molecular Weights of the mixture as low as practicable before alkylation takes place, thus iinishing with as large a fraction as possible within the motor fuel range.

The factors of temperature and pressure in both the olene and oxidation types of reaction above are governed by the nature of the material being treated, Whether liquid or vapor-gaseous at ordinary temperatures and by the type of reaction being carried out. In general, I prefer to carry out these reactions with' all substances in vapor or vapor-gaseousphase. The synthesizing of these nuclear hydrocarbons from the products of vapor phase catalytic oxidation, divides into two classes of reactions as follows:

1. Union of an oleiine and asaturated branched or straight chain hydrocarbon to make a more highly nuclear molecule. Cracking still gases contain the raw material for this synthesis, as does also the hydrocarbon portion of our oxidation vapor-gases, as well as the vapor-gases from the cracking of our oxidizedoil. Where there is a deciency of saturateds, natural gas can be called on to provide them. An example of the above reaction, alkylation (addition or formation of alkyl groups, such as CH3, CaHs and the like to a hydrocarbon chain suchas butane), occurs by the double bond of the olefin with suitable temperature and pressure; :torming a five carbon chain with two branch chains lat one end, each branch. having one carbon drocarbon; (b) acetaldehyde--a product of partial oxidation combines with two molecules of propane from natural gas or the decomposition ofy the oxidation-'product The oxygen of the aldehyde forms water with hydrogen from the propane, .and a branched chain hydrocarbon results which is highly nuclear and of good no knock properties; (c) similarly a ketone' will combine with two molecules of propane, causing water formationresulting in dipropyl diethyl'methane-a highly branched hydrocarbon.

In my United States Patent No. `1,597,796 of August 31, i926, I have described various ways of cracking following partial oxidation of mineral oil and I may use such steps; or I may crack before oxidation to get the cracked and oxidized product Vfor mixingand alkylating. -In oxidizing by my vapor phase process I may use one layer of catalyst, either thin or deep, or I may use separated multiple catalyst layers as shown in my U. S. Patents 2,054,571 or 2,036,215. In the latter case I may introduce saturated hydrocarbons in vapor or gaseous phase between thesuccessive screens, and with or without air or an oxygen-containing gas added. I may also crack the oxidized hydrocarbon catalytically as disclosed in my copending application Ser. No. 283,209, filed July 7, 1939.

The important -novelty of my invention lies in the` presence of oxidized bodies in the cracked mixture. These are present in the gases as well as in the heavier liquid products resulting from cracking. .Hence these desirable reactions can take place during and in the oxidation and cracking operations as well as in an added and separate reforming step for the formation of branched chain hydrocarbons. The advantages of my inventions lie in the higher octane content and slower burning obtained by the treatment of .the partially oxidized, or partially oxidized and cracked material and' the ease and cheapness of reforming where the oxidized bodies or such bodies and olefins are present.

By gaseous phase in my claims, I intend to include vapor phase or true gas phase or both together. Many changes may be made in the catalysts, the temperatures, the percentages of air, etc., without departing from my invention.

I claim:

assume e such` as propylene opening up under the influence of such catalysts as silicates, clays, ,or A1201,

non-aromatic hydrocarbons in gaseous phase into contact with saturated hydrocarbons in the f. nce of an alkylation catalyst under elevated f: 1 lating temperatures 3. In the forming of nuclear, hydrocarbons, the steps consisting of bringing a mixture containing cracked omgen derivativesof normally liquid non-aromatic hydrocarbons in contact with saturated hydrocarbons in the presence o dehydrating and alkylating catalysts. Y

4. In the forming of nuclear hydrocarbons, the steps consisting of lvapor phase omdation of a mixture of heavier and lighter hydrocarbons at an elevated temperature and then subjecting the product to cracking'and alkylating conditions.

5. In the forming of nuclear hydrocarbons, the steps consisting of vapor phase oxidation of a mixture ofA heavier and lighterhydrocarbons at an elevated temperature, then subjecting the product to a. cracking step and then passing the stream over an alkylating catalyst under alkylating conditions.

6. In the forming of 4nuclear hydrocarbons, the steps consisting of bringing af'mixture containing cracked oxygen derivatives of nonaromatic hydrocarbons and unsaturated bodies in contact with saturated hydrocarbons in the presence of an alkylation catalyst under elevated alkylating temperatures.

7. In the forming of nuclear hydrocarbons, the steps consisting of adding saturated hydro-V carbons to a mixture containing partly oxidized hydrocarbons and then subjecting the' mixture"` to dehydrating and alkylating conditions.

8. In the forming of nuclear. hydrocarbons, the I hydrocarbons,v containing a material percentage of oxidized bodies, and alkylating the cracked product in gaseous phase.

12. In the forming of nuclear hydrocarbons,

u the step consisting of cracking and alkylating a.

1.- In the forming' ofnuclear hydrocarbons,

the steps consisting of bringing a mixture containing cracked oxygen derivatives of normally liquid non-aromatic hydrocarbons in contact with saturated hydrocarbons'in the presence of Aan' alkylation catalyst under elevated alkylatin cracked oxygen derivatives of normally liquid partial oxidation product of normally liquid nonaromatic hydrocarbons in gaseous phase.

13.In the manufacture of motor fuels, the steps'. comprising mixing mineral oil vapor and a. gas containing oxygen, passing the mixture through a reactive zone at an elevated temperature under partial oxidation conditions, cracking a product thereof, mixing the cracked material with an added vapor-gas hydrocarbon, and 1alkiylating in the presence of an alkylating cata- 14. In the manufacture of motor fuels.'- the steps comprising mixing mineral oil vapor and a gas containing oxygen, passing the mixture through a reactive zone at an elevated tempera.- ture under partial oxidation conditions,` cracking a product thereof, mixing the cracked material with an added vapor-gas hydrocarbon from one of the preceding steps herein and alkylating in the presence of an alkylating catalyst.

e JOSEPH HIDY JAMES. 

